To get from Schiphol (airport) to Amsterdam is very easy.
When you come out of the baggage claim you enter the Schiphol Plaza (there are shops and restaurants there). Also is the access to trains - Dutch railway is called NS (platforms are below the airport).
Go to the train ticket windows and ask for a single to Amsterdam Central (or Amsterdam CS). They all speak good English so you will have no problems asking for your ticket
Single 2nd class ticket is around €3.60 plus €0.50 transaction fee. The journey to Amsterdam CS takes 15 minutes.
The ticket office person will tell you the next train time and the platform if you ask them

or you can just check on one of the time table boards.
Should be a train every 5 mins. approx.
You can also check on the NS website for train times and prices:
http://www.ns.nl/servlet/Satellite?...rplus2stap&action=js1&p=1083234338201&lang=en
I've used this website to book hotels in Holland:
http://www.hotels.nl/
You can get some good deals.
Last time I stayed in Amsterdam I stayed at the Barbizon Palace, it's a bit pricey but just across the road from the station.
A work colleague has always stayed at the Victoria Hotel - also oposite the station.